The Orbit of Spitzer

The Spitzer Space Telescope is an infrared telescope. To avoid infrared radiation emitted by Earth, Spitzer is placed in an Earth-trailing orbit. It follows the Earth around the Sun, but from a distance. Each year, it falls about 0.1 AU further behind the Earth. Eventually, it will work its way around the Sun and approach Earth from the other side. Spitzer is in a chaotic horseshoe orbit.

The simulation Spitzer.gsim shows the orbit of the Spitzer Space Telescope in a rotating frame to keep Earth stationary. Watch as Spitzer distances itself from Earth, only to approach Earth from the other side. Once there, Earth seemingly repels Spitzer back around the Sun in the other direction.